This story appeared just recently. While I can pretty much guess what caused the dual engine failure, the interesting part is their survival at sea. It will definitely make any open water seaplane pilot think about being prepared to cope with such an emergency.
One survival principle that was hammered into me was that if you're not wearing it when the accident happens, it's unlikely you're going to have it to use after the accident. A ten man raft and a 50 pound survival pack is great ...... unless it goes down when the aircraft sinks or burns up in the post-crash fire.